EF1 tornado in Clark County, Illinois

This tornado crossed from Crawford County into southern Clark County about 0.5 miles west of West York at 6:48 PM CDT. It continued eastward, causing EF-1 damage to trees and a farm outbuilding on the west side of the town of York before crossing the Wabash River into the National Weather Service Indianapolis County Warning Area in Sullivan County, Indiana at 6:54 PM CDT.

Scattered supercell thunderstorms developed in the vicinity of a nearly stationary frontal boundary draped along I-70 during the afternoon and early evening of May 16th. The storms first formed along a Springfield to Saint Louis line, then tracked east-northeastward generally south of the I-72 corridor, causing sporadic wind damage...most notably in the Decatur and Effingham areas. In addition, the highly unstable airmass to the south created vigorous storm updrafts which supported very large hail. Upon initial storm development, a few stones as large as golf balls occurred on the southeast side of Springfield to near Riverton. However, an even stronger cell later in the afternoon dropped 3-inch diameter hail (larger than a baseball) in Robinson in Crawford County. Another nearby storm produced an EF-1 tornado that tracked across portions of northern Crawford and southern Clark County before crossing the Wabash River into Sullivan County, Indiana.